A liquid crystal display device is provided with an effective display area formed by display pixels in a matrix shape. The effective display area is provided with a plurality of scan lines extending along the row direction of the display pixels and a plurality of data lines extending along the column direction of the display pixels. Switch elements and pixel electrodes connected with the switch elements are arranged at intersections of the scan lines and the data lines. The switch elements are, for example, thin film transistors (TFTs), and the switch elements can respond to signals supplied to each scan line and send the signals from the data lines to each corresponding pixel electrode. The scan lines and the data lines extend to the peripheral part of the effective display area (for example, the scan lines and data lines are connected with a drive circuit), and the quality of pictures displayed in the effective display area is tested by inputting test signals at the peripheral part. The scan lines, the data lines and other circuit connecting lines are usually collectively referred to as signal lines.
With the increase of display pixel density, various signal lines such as the scan lines and the data lines in the effective display area and the peripheral part thereof are thinner and thinner in line width, and intervals are smaller and smaller, so various poor wiring conditions such as line breakage and short circuits are more likely. Therefore, for timely discovery of the poor wiring conditions, preventing large-scale poor conditions and preventing rejects from entering the next procedure to cause the waste of materials, the scan lines, the data lines and other signal lines are required to be checked after wiring so as to determine whether the poor wiring conditions exist or not.
At present, a common detecting method for the liquid crystal display device is that respective signal lines are connected together by using a plurality of shorting bars, test signals are input to the shorting bars, the test signals are transmitted to the scan lines and the data lines of the effective display area through corresponding elements, and the quality of the pictures displayed in the effective display area is detected.
An example is shown in FIG. 1, which is a structural schematic diagram of a liquid crystal display device. The liquid crystal display device comprises four shorting bars 101, 102, 103 and 104, test terminals 101a, 102a, 103a and 104a connected with the four shorting bars 101, 102, 103 and 104 respectively, six data lines D11, D12, D13, D14, D15 and D16, twelve connecting lines C1, C2, C3, C4, C5, C6, C7-1, C7-2, C8-1, C8-2, C9-1 and C9-2, three scan lines G11, G12 and G13, thin film transistors 105 and 106, through holes 107 and 108, and a switch control line 109.
In this case, the data lines D11 and D14 are red signal data lines, the data lines D12 and D15 are green signal data lines, and the data lines D13 and D16 are blue signal data lines. The data lines D11, D12, D13, D14, D15 and D16 are electrically connected with the connecting lines C1, C2, C3, C4, C5 and C6 through the thin film transistor 105 respectively. The connecting lines C1, C4 and the shorting bar 101, the connecting lines C2, C5 and the shorting bar 102, and the connecting lines C3, C6 and the shorting bar 103 are electrically connected through the through holes 107 and connecting metals (not shown in the figure) respectively. The scan lines G11, G12 and G13 are electrically connected with the connecting lines C7-1, C8-1 and C9-1 through the through holes 108 and connecting metals (not shown in the figure) respectively; the connecting lines C7-1, C8-1 and C9-1 and the connecting lines C7-2, C8-2 and C9-2 all intersect with the switch control line 109; and switch elements 106 are respectively formed at an intersection points of the connecting lines C7-1 and C7-2 and the switch control line 109, an intersection points of the connecting lines C8-1 and C8-2 and the switch control line 109 and an intersection points of the connecting lines C9-1 and C9-2 and the switch control line 109, so that the scan lines G11, G12 and G13 are electrically connected with the shorting bar 104 through the through holes 108, the connecting metals, the connecting lines C7-1, C8-1 and C9-1, the connecting lines C7-2, C8-2 and C9-2 and the switch elements 106.
The shorting bars 101, 102 and 103 electrically connected with the data lines are called data line shorting bars. The shorting bar 104 connected with the scan lines is called a scan line shorting bar.
Generally speaking, the shorting bars 101, 102 and 103 and the connecting lines C1, C2, C3, C4, C5 and C6 are in different circuit layers (not formed in a same step), so the shorting bars 101, 102 and 103 are electrically connected with the corresponding connecting lines through the through holes 107. In detail, each through hole 107 comprises through holes 107-1 and 107-2, for example, the through hole 107-1 of the shorting bar 101 is electrically connected with the through hole 107-2 of the connecting line C4 through connecting metals (not shown in the figure), so that the shorting bar 101 is connected with the data line D14, and connecting modes of the other shorting bars and connecting lines are similar thereto. The connecting metals are generally indium tin oxide (ITO) or indium zinc oxide (IZO). Electric test can be carried out through inputting test signals to the test terminals 101a, 102a, 103a and 104a. 
The shorting bars 101, 102 and 103 and the connecting lines C1, C2, C3, C4, C5 and C6 are positioned in different circuit layers, because overline connections are required between the shorting bar 101 and the connecting lines C1, C4 and between the shorting bar 102 and the connecting lines C2, C5. As shown in FIG. 1, the connecting line C1 is required to span the shorting bars 102 and 103 to be connected with the shorting bar 101. If the connecting lines and the shorting bars are formed in the same circuit layer, the connecting line C1 and the shorting bars 102 and 103 will be shorted.
Therefore, the liquid crystal display device has the following defects:
firstly, in the manufacturing process of the liquid crystal display device, for example, in the procedures of picking and placing glass in array process, coating an alignment film and rubbing the alignment film in box process and the like, the ITO or the IZO at the through holes 107 is often burnt due to high static electricity; due to the through hole defect, the antistatic function of the shorting bars is disabled and also an array substrate experiences a phenomenon of poor display when testing electrical property, so that the product is scrapped; and
because each data line corresponds to a connecting line, the data lines D11, D12, D13, D14, D15 and D16 and the connecting lines C1, C2, C3, C4, C5 and C6 occupy a relatively larger area, which is adverse to reduce the size occupied by the test signal control part; and furthermore, because more data lines are superposed with the switch control line 109, switch signals of the switch elements are delayed.